Conventionally, a fuel vapor leakage detection device is known. A fuel vapor leakage detection device may be configured to detect leakage of fuel vapor from a fuel tank, which is installed in a vehicle, and a canister, which adsorbs fuel vapor generated in the fuel tank, and/or the like. A fuel vapor leakage detection device may include an atmospheric passage, a tank passage, a switching valve, a pump and/or the like. The atmospheric passage may be communicated with the atmosphere. The tank passage may be communicated with the fuel tank. The switching valve may switch communication and blockade between the atmospheric passage and the tank passage. The pump may depressurize the fuel tank through the tank passage. When an engine of a vehicle is stopped, the fuel vapor leakage detection device may drive the pump to depressurize the interior of the fuel tank through the tank passage. The fuel vapor leakage detection device may detect pressure change in the state thereby to detect leakage of fuel vapor from the fuel tank, the canister, and/or the like.
To the contrary, when the engine is in operation, the fuel vapor leakage detection device may communicate the atmospheric passage with the tank passage and to flow air from those passages through the canister into an engine intake passage, thereby to purge vapor fuel, which is absorbed in the canister, into the engine intake passage. In addition, when fuel is supplied into the fuel tank, the fuel vapor leakage detection device may enable to communicate the atmospheric passage with the tank passage to draw atmospheric air from those passages into the fuel tank, before a fueling port of the fuel tank is opened. In this way, the fuel vapor leakage detection device may enable to manipulate pressure in the fuel tank to be close to the atmospheric pressure.
A fuel vapor leakage detection device disclosed in Patent Document 1 includes a filter case and a housing, which are integrated with each other. The filter case accommodates a filter element, which captures dust contained in air drawn into the atmospheric passage. The housing accommodates a switching valve, a pump, and/or the like.
(Patent Document 1)
Publication of unexamined Japanese patent application No. 2012-117381
As the filter element captures dust, the captured duct may be deposited on the filter element to clog the filter element.